Railway signaling system



Oct. 28, 1941.

A. BROWN ET AL RAILWAY SIGNALING SYSTEM Filed Oct. 25, 1959 3 Sheets-Sheet l N MQ WW Qv Patented Oct. 28, 1941 RAILWAY SIGNALING SYSTEM Andrew Brown and Thomas Alfred Marshall, London, England, assignors to International Standard Electric Corporation, New York, N. Y.

Application October 25, 1939, Serial No. 301,308 In Great Britain October 7, 1938 2 Claims.

This invention relates to railway signal and points control equipment.

In railway signal and points practice, it is necessary to provide stringent checks between the various signals and points in order to determine, when setting up a route and freeing it to oncoming trafilc, that all signals and points which are inter-related with those directly concerned in setting up the route are in such positions that no other conflicting route is simultaneously set up and freed, and that no other possible source of interference or trouble exists.

In United States Patent No. 2,241,906, granted May 13, 1941, and British Patent 496,495, accepted November 30, 1938, thereis disclosed a railway signal and points control equipment comprising a number of panel control keys of which any one can be set to select a certain route, a number of multi-position switches of which any one can be set in response to the setting of a panel control key to an off-normal position distinctive of the said selected route, and means for setting the appropriate track equipment, i. e., the signals and/ or points, in accordance with the setting of the said multi-position switch. Each multi-position switch, which may be of the type used in the rotary system of automatic telephony and known as sequence switches, includes a normally disengaged clutch which can be electromagnetically engaged with a rotating driving shaft. The electrical circuit for causing clutch engagement in response to the setting of the .panel control key includes contacts which can only be closed provided that no other multiposition switch is in a position to set up a conflicting route, and further contacts which can only be closed provided that no other multiposition switchis in motion. The object of the present invention is to reduce the number of relays and relay contacts associated with each multi-position switch as compared with the systems described in Patent No. 2,241,906.

The invention will be clearly understood from the following description of one embodiment thereof shownin the accompanying drawings, which shows the control circuits of one of the five sequence switches of the interlocking system described in Patent No. 2,241,906, together with the lookout circuit for all the sequence switches.

In prior British patent specification #496,495, a group of RC contacts was required in series with each clutch magnet in order to prevent simultaneous rotation of any two switches carrying conflicting routes. This system would still permit the simultaneous rotation of two sequence switches where none of the routes on one sequence switch conflicts with any of the routes on the other.

It is now proposed to provide a complete lockout between sequence-switch driving-clutches, so that it will be impossible for any two switches to revolve simultaneously.

It is found in practice that the additional delay occasioned by preventing the simultaneous rotation of non-conflicting switches, is quite negligible and is easily outweighed by the simplification obtained by the adoption of a universal lock-out circuit. 1

Fig. 1 illustrates diagrammatically a lock-out circuit arrangement in accordance with my invention,

Figs. 2 and 2A taken together show the control circuit for sequence switch I of Fig. 1.

Since the present invention relates primarily to the control mechanism for the sequence switch clutches the general circuit has been shown only diagrammatically in Fig. 1. The five sequence or other rotary switches are shown at l, 2, 3, 4 and 5. No illustration of the interlocking cam arrangements of these switches is shown and the selective operating keys are merely indicated schematically since the details of these parts are unimportant to the invention. The circuits through switches l--5 have been indicated by straight lines except in the output of switch 5 where separate lines to relays IR, 2R, 3R, 4R, and SR are illustrated. These relays correspond to the R relays described in the aforementioned application and are used in completing a circuit for the motor start relay MS.

When a desired route is selected it is necessary that one or more of sequence switches |5 be rotated to the proper position for establishing such route. However, if a conflicting route is in existence at the time, the circuit for the R relay corresponding to the selected route is not completed so that the selected route cannot be set up so long as the conflict exists.

It is also desired that if a route is in the process of being set up by rotation of a sequence switch, initiation of selection of a second route which may conflict with said route being set up should not be efiected. In accordance with this invention such initiation is prevented by provision of an interlock in the clutch magnets IRC,

2R0, 3R0, 4R0, 5RC, so that only one sequence Switch may be in motion at one time.

route selecting key, indicated diagrammatically in Figs. 2 and 2A, for relay IR, from positive, cams of one or more of sequence: switches I--5-, winding of relay IR to negative. Relay IR will operate closing its contacts W2 establishing a circuit for clutch magnet, IRC and motor start relay MS from positive, winding magnet I'RC,

normally closed contacts 2'102, 3rc2', 4102, 15102 winding MS to negative. Energization of) MS will start the motor and energization of RC will. operate its clutch causing switch I to rotate until the circuit for IR is opened by the switch reaching its selected position. Deenergization of relay IR opens the circuit of. magnet. IRC which releases" the clutch of switch I, stopping its rotation upon deenergization. Magnet IRC while energized also opens its contacts Irc preventing completion of circuits for magnets: ZRC, 3RC, 4RC, 5RC while switch I is in operation.

Suppose now the selected route callsfor operation of switch 3 after switch I' has been positioned. A circuit will thus be established for relay 3R assuming no conflict exists in a manner similar to that. described for IR.

Relay 3R operates closing its normally open contacts 3T2 and establishing a circuit for clutch magnet 3RC and motor start relay MS from posiright and breaking the negative lead' for magnets to its left. Accordingly, only one switch can. be in motion at any one time. 1 r

In Figs. 2 and 2A a more specific circuit diagram showingthe control circuit for. sequence switch I is shown. It should be understood that a similar circuit is utilized for each of the sequence switches.

A brief explanationof the conventions used in Figs. 2 and EA willserve tosimplify the description. The contacts controlled by the various relays areshown by open arrowheads, those above the line indicatingfront contacts and those 'below the line indicating back contacts; -The arrowheads contacting the line indicate that the contacts are'normally closed and those spaced from the line indicate contacts normally open. The relays and armatu-resare separated in order not tounduly complicatethe circuits, the relays being indicated generally by upper case. letters and their contacts by lower case letters, correspondi-ng letters being used for the relays and contacts. K J I The. five sequence switches are. designated by numbers I, 2, 3;. 4 and 5', and the separate cams 'thereof by a letterfollowing-the number as 2A, 75

3F, etc. The contact positions at which the cam closes a circuit are generally indicated by the numerals following the letter. Other conventions for the cams are set forth below.

The well known sequence switch is of the general type illustrated in the patent to Reynolds 1,127,808, February 9, 1915, and may consist of a plurality of discs or cams rotatable with a driving spindle and cooperating brushes. The discs or cams may be of metal separated by insulation,

. the metal parts being cut away in part so that in certain positions the brushes associated with a particular disc donot close a circuit; The switch spindle is rotated to a number of positions correspending to desired settings and in each position will complete selected ones of the circuits associated therewith. In the preferred arrangement each switch is provided with a magnetically controlled clutch for coupling the spindle to a motor for securing the desired drive.

The convention shown for cam A represents the master control cam of the sequence switch cut to break contact in each of the respective route setting positions.

The convention shown for ca-m L represents a cam making contact only in the position specified, i'. e. the home position. The convention shown for cam F, of sequence switch 3, represents a cam making contact in every position except those specified, i. e. the circuitis broken when the sequence switch is in the positions corresponding to routes I or 3, but made in every other position. The convention shown for cams D and E in sequence switch 2 represents two adjacent copper cams connected together by metalrivets and each breaking their appropriate circuits in'positions I5 and I-6r, andZ and 4 respectively.

Similarly, the pairs of cams on sequence switch No. I, B and C, and D and E are riveted together and the adjacent pairs B.C, D -E and F are connected on the sequence switch rotor without the need for external wiring. The wipers shown contacting with cam C would. make contact continuously from the home position toroute 6 andi from the home position to route 5 respectively- I Consider-the procedure for. setting up a route. Let; us assumexthat the signalman attempts tovset-up'a' route No. 5 indicated by 5(R) in Fig. 2

by reversing; panel control. switch No. '5. The in.- dividual. panel switches "indicated. by a.v numeral an'dl'R) are-normally open. and each switch ,(R)

is. mechanically coupled. with a normally closed switch ('N'i', Fig: 2A,. as described in' British Patent 49.6 4595; referred. to above; Assuming thatNo. I sequence switch. is in its home position and that sequence switches 3; 4i and 2 are. not stand-.- ing in theconfiicting. route positions. I, 3, 8, 9, I5 or: I6, then'fa .circuit' will: be completed for the relay JIR': from. positive, over cam F of sequence switch 3, cam F of sequence switch. 4,. cam D of [a sequence switch; 2, panel. switch 5'(R) reversed,

moved'. from. circuit, as explained in connection withiliig'l'. I

:When the clutch magnet IRC'operates in re sponsetoithe relay IR. the-sequenceswitch Iw-ill revolve out of the home position H and the circuit already described for relay IR will be broken by cam IB. The relay IR will remain energised over the A cam until the sequence switch reaches the position corresponding to route 5, whereupon relay IR, and consequently clutch magnet IRC, will be deenergised and the switch will come to rest.

The relay I PR is then operated over back contacts Irc3, Fig. 2, cam IX in route position 5, panel switch 5, cams 2D, 4F and 3F provided that circuits through the interlocking sequence switches and the panel control key remain intact. Sequence switch I in position 5, in conjunction with relay IPR operated, will thereupon set the necessary points and clear the'signal for route 5, subject to the usual point and signal control requirements. The circuit originally traced for relay IR was broken by cam IL which is no longer in its home position and the sequence switch can only be driven home by contacts IyrZ after proving that it is safe for route 5 to be restored to normal.

The restoration of the route setting will now be considered referring more particularly to Fig. 2A. As soon as panel switch 5(R) is moved out of reverse position the circuit for relay IPR, Fig. 2, will be broken and the circuit at 5(N) closed. Relay IPR will release and contacts 5/ B/Ih, Fig. 2A, will be closed by circuit arrangements not shown, since they have no bearing on the present invention.

A circuit is then provided for relay IYR, from positive, contact I'rc I, cam N of sequence switch I, panel switch 5(N) in normal position, contacts 5/6/Ih, track contacts IIIBTR, IMTR, winding IYR to negative. In event track 3 is occupied contact 38R will complete a circuit for IYR independently of track relays I05TR, IMTR.

Energization of relay IYR closes a circuit for relay IR at Ig TZ, Fig. 2, independently of cam A of switch I to start the switch after which it will be returned to home position under control of cam A of switch I.

The details for alternative circuit in Figs. 2 and 2A are not described since they are not needed for an understanding of this invention. The more or less complete circuit is shown, however, to clearly show the relation of this circuit with respect to that described in application Ser. No. 209,198 mentioned above.

What is claimed is:

1. In railway routing control equipment having a manual means for selecting a route, a plurality of multi-position switches of which any one can be set to a position distinctive of the said selected route, an electromagnetically operated clutch for each multi-position switch drive means, means for selectively operating said multi-position switches comprising clutch magnets selectively energised in response to the settingof the manual selecting means for operating a corre-. sponding one of said clutches for coupling'one of said switches to said driven means to drive the said multi-position switch to the route-distinctive position, a common pair of feed lines across which said clutch magnets are arranged in parallel, the connections to one line being in reverse order to the connections to the other with respect to a feed terminal at one end of each line for the clutch magnets, and two pairs of normally-closed contacts which are opened when the respective clutch magnet is energised, connected one in each feed line between the junction to the feed line of the said magnet and the junction to the feed line of the next magnet away from the feed terminal.

2. In railway routing control equipment having manual means for selecting a route, a plurality of multi-position switches of which any one can be set to a position distinctive of said selected route, an electromagnetically operated clutch for each multi-position switch, drive means for said clutches, means for selectively operating said multi-position switches comprising electromagnetic clutch operating means for selectively operating said clutches to couple a selected one of said switches to said drive means, circuit connections for said clutch operating means, means responsive to operation of said manual means for completing an operating circuit for a selected one of said electromagnetic clutch operating means, and means responsive to operation of said selected clutch operating means for preventing completion of an operating circuit for the other clutch operating means. I

ANDREW BROWN. I

THOMAS ALFRED MARSHALL. 

